Phosphinedichloromethylenes



United States Patent ical Company, St. Louis, Mo., a corporation ofDelaware No Drawing. Filed Nov. 29, 196 1, Ser. No. 155,818

Claims. (Cl. 260-6065) This invention relates to a new and useful classof compounds and to the preparation of same.

'Ilhe compounds of this invention are phosphinedichloromethylenes of theformula wherein R, R and R are like or unlike, contain from 1 to 12carbon atoms and are either alkyl, or alkoxyalkyl or chloroalkylradicals Exemplaryof R, R and R" are methyl, ethyl, propyl, butyl, amyl,hexylpoctyl, decyl, dodecyl, and the various isomeric alkyl formsthereof, methoxyethyl, ethoxyethyl, propoxyethyl, amyloxyethyl,decyloxyethyl, ethoxyethoxyethyl, methoxypropyl, and the variousisomeric alkoxyalkyl forms thereof containing up to twelve carbon atoms,chloromethyl, ehloroethyl, chlorobutyl, diehlorobutyl, chlorohexyl,chlorodecyl, and the various isomeric chloroalkyl forms thereofcontaining up to twelve carbon atoms. In general it is preferred thatthe respective R, R and R" groups be alkyl radicals containing 1 to 8carbon atoms.

I The phosphinedichloromethylenesof this invention are prepared byreacting trialiphatic phosphine of the formula RPR" wherein R, R and Rhave the :aforedescri-bed significance with dichlorocarbene :CCI

Dichlorocarbene is a well known material and methods for its preparationare Well described in the literature. For example, it is prepared in ananhydrous system by (1) Replacing an alkali metal lower alkoxide withchloroform,

(2) Heating chloroform in the presence of phenyl lithium,

(3) Heating salts of trichloroacetic acid,

(4) Heating esters of trichloroacetic acid in the presenceof alkalimetal lower alkoxide.

' Dichlorocarbene prepared by any of the known methods for itspreparation is unstable but when prepared in the presence oftrialiphatic phospines of the formula wherein R, R and R" have theaforedescribed significance, it reacts spontaneously to. form. thephosphinedichloromethylenes of this invention.

The trialiphatic phosphinesuseful in preparing thephosphinedichloromethylenes include trimethyl phosphine, triethyl.phosphine, the various tripropyl phosphines, tributyl phosphines,tn'amyl phosphiries, trihexyl phosphines, trioctyl phosphines, tridecylphosphines, tridodecyl phosphines, tri(chloromethyl) phosphine, thevarious tri(chloropropyl) phosphines, tri(chlorobutyl) phosphines,tri(chlorohexyl) phosphines, tri(methoxy- 'ethyl) phosphine,tri(ethoxyethyl) phosphine, the various. tri(propoxyethy1) phosphines,(dimethyl) (ethyl) "phosphine, (diethyl) (methyl) phosphine, (diethyl)'(propyl) phosphine, (diethyl) (isoamyl) phosphine, '(dirnethyl)(methoxyethyl) phosphine, (dimethyl) (chlo romethyl) phosphine, and thelike. The preferred trialiphatic phosphines are those of theforegoingstructure wherein R, R and R" are alkyl radicals containing '1 to 8carbon atoms.

The abovedescribed dichlorocarbene reactant of the process of thisinvention is generated in situ, and reacts immediately with thetrialiphatic phosphine to provide the phosphinedichloromethylenes ofthis invention. In that the phosphinedichloromethylenes are sensitive towater the process of this invention is preferably conducted in ananhydrous inerto'rganic liquid media. Suitable liquid media includepentane, hexane, heptane, cyclohexane, benzene, toluene, xylene, andlike inert liquid hydrocarbons, and also diethyl ether, diisopropylether, tetrahydrofuran, etc. While a wide range of reaction temperaturescan be employed provided the system is fluid (Le. a reaction temperatureabove the freezing point of the system. up to and including the boilingpoint of the system) the optimum temperature will be that required togenerate the dichlorocarbene. The preferred reaction temperature is thatwhich produces a substantially quantitative yield of dichlorocarbenefrom the chlorine containing precursor therefor and which enables arapid and substantially complete reaction of dichlorocarbene andtrialiphatic phosphine.

To illustrate the preparation of the phosphinedichloromethylenes of.this invention is the following:

Ex m I To a suitable reaction vessel equipped with an agitator andthermometer is charged 20.2 grams of t-ri(n butyl) phosphine, 12.0 gramsof chloroform and 50 ml. of n-heptane. While agitating the mass iscooled to about 35 C. and while maintaining the agitating mass at 30 C.to -40 C. there is added over a 30 minute period -18.6 grams of an'anhydrous equimolecular mixture of potassium t-butoxide and t-butanoland 300 ml. of n heptane. A yellow suspension results, the yellow soliddispersed therein is identified astri(n-butyl)phosphinedichloromethylene. Since this yellow solid isreactive with moisture it is preferably kept in suspension in theanhydrous inert organic liquid medium (n-heptane in this instance) andunder a nitrogen atmosphere until used.

Upon adding 4,4'-dichlorobenzophenone in the form of a diethyl ethersolution thereof to the yellow suspension of Example I in the cold (0-5"C.) and under a nitrogen atmosphere a suspension of tri(n-butyl)phosph'ine oxide and l,1-di-(4-chlorophenyl)-2,2-dichloroethylene isobtained. Upon recovering -1,1-di-(4-chloro phenyl)-2,2-diohloroethylenefrom the suspension and hydro-chlorinating same the well knowninsecticide DDT a mixture of t-butanol and n-heptane.

Example A Employing the process of Example I but replacing chloroformwith an equimolecular amount ofbromoform ,failed to yieldtri(n-butyl)phosphinedibromomethylene.

Example II Employing the procedure of Example I but replacingtri(n-hutyl) phosphine with an equimolecular amount of 't-ri(2-ethylhexyl) phosphine there is obtained tri-(Z-lethylhexyl)phosphinedichloromethylene.

Example III Employing the procedure of Example I but replacingtri(n-buty1) phosphine with an equimolecular amount oftri(2-ethoxyethyl) phosphine there is obtained tri(2-ethoxyethyl)phosphinedichloromethylene.

Example IV Employing the procedure of Example I but replacingtri(n-butyl) phosphine with an equimolecular amount of triethylphosphine there is obtained triethylphosphinedichloromethylene.

Example V Employing the procedure of Example I but replacingtri(n-butyl) phosphine with an equimolecular amount of triisopropylphosphine there is obtained triisopropylphosphinediohloromethylene.

Example VI Employing the procedure of Example I but replacing theanhydrous equimolecular mixture of potassium t-butoxide and t-butanolwith 11.2 grams of anhydrous potassium t-butoxide tri(n-butyl)phosphinedichloromethylene is obtained in a comparable yield.

Example VII Employing the procedure of Example I but replacingtri(n-butyl) phosphine with an equimolecular amount oftri(2-chloroethyl) phosphine there is obtainedtri(2-chloroethyl)phosphinedichloromethylene.

Example VIII Upon mixing equimolecular amounts of tri(n-butyl) phosphineand sodium a,a,a-trichloroacetate in benzene and refluxing the mixturetri(n-bntyl)phosphinedichloromethylene is obtained.

Example IX Employing the procedure of Example I but replacing potassiumt-butoxide with an equimolecular amount of phenyl lithium and omittingt-butanol there is obtained tri n-butyl phosphinedichloromethylene.

Other phosphinedichloromethylenes of this invention obtained by theprocesses hereinbefore described include:

Trimethylphosphinedichloromethylene Triisobutylphosphinedichloromethylene Triisohexylphosphinedichloromethylene Tri (n-dode cyl)phosphine dichloromethylene Tri 2-i sopropoxyethyl) phosphinedichloromethylene Tri 4-chlorobutyl phosphinedichl oromethyleneTri (2,3 -dichloropropyl) phosphinedichloromethylene (Methyl) die thyl)pho sphinedichloromethylene (Ethyl) (di-n-butylphosphinediohloromethylene (Diethyl) (4-chlorobutyl) phosphinedichloromethylene (Diethyl) (2-ethoxyethyl phosphinedichloromethyleneThe phosphinedichloromethylenes of this invention have toxic effects anvarious animal organisms and have utility as agricultural toxicants inthe control of insects, nematodes and fungi. The new compounds haveadditional utility as intermediates in the preparation of knowncompounds described in the Journal of the American Chemical Society,vol. 4 8, p. 3144 (1926), for example any of the aforedescribedphosphinedichloromethylenes upon reacting with benzophenone provide1,1-dipheny1- 2,2-dichloroethylene. To illustrate such is the following:

Example B To a suitable reaction vessel equipped with a thermometer andagitator is charged 20.2 grams of tri(nbutyl) phosphine, 12.0 grams ofchloroform, and 50 ml. of n-heptane. The mass is cooled to about 35 C.and while agitating 18.6 parts by weight of an anhydrous equimolecularmixture of potassium t-butoxide and t-butanol and 300 ml. of n-heptaneis added over a 30 minute period. After the addition 18 parts by weightof benzophenone is added in the form of a diethyl ether solution thereofwhile maintaining the temperature at about C. A nitrogen atmosphere ismaintained in the reaction vessel at all times. After a 16 hour periodthe reaction mass is filtered and the filtrate is evaporated to dryness.The residue is dissolved in a benzene/hexane mixture from whichtri(n-butyl) phosphine oxide precipitates. The mass is filtered and thefiltrate is evaporated to dryness. The residue is1,1-diphenyl-2,2-dichloro-ethylene which after recrystallizing fromaqueous ethanol gave a melting point of 79-80" C.

This application is a continuation-in-part of copending applicationSerial No. 862,481, filed December 29, 1959, and now abandoned.

What is claimed is:

1. A phosphinedichloromethylene of the formula R R P=OC12 wherein R, R'and R respectively contain from 1 to 12 carbon atoms and are selectedfrom the group consisting of alkyl, alkoxyalkyl and chloroalkyl.

2. A phosphinedichloromethylene of the formula RP=C 01:

wherein R, R and R" are alkyl radicals containing 1 to 8 carbon atoms.

3. Tri(n-butyl)phosphinedichloremethylene 4.Triethylphosphinedichloromethylene 5.Triisopropylphosphinedichloromethylene 6.Tri(2Pethylhexyl)phosphinedichloromethylene 7. The method of making aphosphinedichloromethylene of claim 1 which comprises reacting phosphineof the formula R-P-R" wherein R, R and R" respectively contain from 1 to12 carbon atoms and are selected from the group consisting of alkyl,alkoxyalkyl and chloroalkyl, with dichlorocarbene generated in situ inan inert anhydrous organic liquid medium.

8. The method of making a phosphinedichloromethylene of the formulawherein R, R and R" are alkyl radicals containing 1 to 8 carbon atomswhich comprises reacting phosphine of the formula RPR 1'1 wherein R, Rand R" have the abovedescribed significance with dichlorocarbenegenerated in situ in an inert anhydrous liquid organic medium.

9. The method of making a phosphinedichloromethylene of the formula R ar- 001i No references cited.

1. A PHOSPHINEDICHLOROMETHYLENE OF THE FORMULA
 7. THE METHOD OF MAKING APHOSPHINEDICHLOROMETHYLENE OF CLAIM 1 WHICH COMPRISES REACTING PHOSPHINEOF THE FORMULA